1. Field
The present disclosure is directed to a method and apparatus for transmit power calibration in a frequency division multiplexed wireless system. More particularly, the present disclosure is directed to mapping a power control calibration region to an uplink symbol in a subframe.
2. Introduction
Presently, efforts are currently underway to standardize uplink power control for Third Generation Partnership Project (3GPP) Long Term Evolution (LTE), also referred to as Evolved Universal Terrestrial Radio Access (EUTRA). While exact implementation details are yet to be finalized, it is generally understood that terminals, such as user equipment (UE), in a EUTRA network will have to transmit at a certain power level that is determined by a specific power control formula. It is also generally understood that, for each UE, the power control formula attempts to maintain the per subcarrier power, such as power spectral density (PSD) received at the base station at a desired level. If the received PSD has to be kept at a particular level, and the number of subcarriers allocated to a UE is significantly different in each subframe, then total transmit power of each EUTRA UE will change considerably from subframe to subframe. Maintaining transmit power accuracy, with rapidly changing transmission bandwidth and transmission frequency, such as separate sets of subcarriers that may be allocated in different subframes, will be a significant challenge for UE hardware implementation. Without any mitigation mechanisms in place, UEs in the EUTRA network will make significant errors in the transmit power resulting in a considerable loss in spectral efficiency.
Thus, there is a need for a method and apparatus for transmit power calibration in a frequency division multiplexed wireless system.